[DevTools] Added keyboard search while in sources
While in sources file explorer gives the ability to search/filter files
by typing while panel is not blured. On blur event, click, esc or enter
the filtering will cancel.
The display underlines the matches found. If the user then uses arrow keys
to navigate up and down only the filtered items should be selectable.
R=lushnikov,pfeldman
BUG=594654
Review URL: https://codereview.chromium.org/1831903002
Cr-Commit-Position: refs/heads/master@{#387079}
3 files changed
